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cutting teeth are pushed around a track
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I don't know if this has been done, maybe the materials, milling capabilities were not up to the task.

On a regular chainsaw, the chain actually means there is only one plane the chain can cut. What if the teeth were independent but pushed each other along.

The tooth as a whole component would act like a curtain hook which slides in a track. The tooth has three components, the cutting surface, the bearing part, that moves with the other teeth either side, and the connection system hooked into the track. The connection system also bears the drive force from the motor.

I was thinking that this way of making moving teeth opens up all sorts of possibilities. Cutting in only certain areas, teeth are tracked out of the way. All shapes that a chain can't form such as a concave curve. On a cylinder the track could spiral and with a tube the teeth could return down the centre.

Thinking like train tracks or dominoes, the track could even split and join giving multiple cutting tracks with moving teeth. Admittedly the tooth bearing surfaces will have to be more complex. Think zip links.

I was thinking the motion could be hydraulic, pneumatic but speed and sealing might be a problem so a cog system might be the best.

Looking at this idea, Death knew exactly what Death wanted Father Christmas to bring , on his early morning visit.

wjt, Dec 09 2015


       This might just be one of those brilliant ideas that would have made you very rich, had you not disclosed it here. I'm sure there are industrial applications for a saw that can cut complex curves as this one could.   

       You could, for instance, have a track in the form of a rounded-corner rectangle (or any other shape), thereby cutting said shape in a single plunge without the hassle of moving a jigsaw/bandsaw around.   

       If I were you, I'd delete this before anyone notices, and go build a prototype.
MaxwellBuchanan, Dec 09 2015

       On a chainsaw, there are no rollers, just tabs that ride in a slot flooded with chain oil. I think this is because anything more complex would be prone to jamming with swarf. Even so the blade is worn down in a matter of weeks. There's also a substantial amount of centrifugal force, you wouldn't want individual teeth escaping.
mitxela, Dec 09 2015

       Yes, but that wouldn't stop the idea from working. As I see it, you have basically the same mechanism, except that   

       (a) the teeth are held into a wrapped-round C- shaped track, instead of conforming to a U-shaped one due to chain tension and   

       (b) teeth are pushed along the track by the teeth behind them, instead of being pulled by the chain.   

       One concern, though. Pulled chains tend to be stable against jamming. In contrast, a series of things being pushed would be prone to jam: if one tooth sticks, another will ram up against the back of it and potentially drive it sideways (sort of "buckling" the line of teeth).   

       However, this problem could be overcome: the teeth can still be linked in a chain and pulled along the curved track, as long as the linkages can flex from side to side to go around curves.   

       But then again, again, this then becomes a bit like a conventional chainsaw (where the chain flexes to go around the tip of the blade), but with the cutting teeth set at right-angles to the blade of the chainsaw.   

       You could make a sort of prototype of this if you:   

       (1) Take a regular chainsaw
(2) Grind off the teeth to leave just the chain
(3) Also cut out most of the metal of the chainsaw blade, leaving just the outer edge to support the chain
(4) Weld new teeth onto each chain link, at right- angles to the original teeth.

       This would only let you make U-shaped cuts, similar to the shape of the original chainsaw blade, but it would prove the concept.
MaxwellBuchanan, Dec 09 2015

       eh, you're all jammed with swarf. Go jam it with swarf, you bunch. Heh. Swarf. New word!   

       My question for wjt: currently chainsaw teeth are pushed along / pulled along by the chain. Now there is no chain. Yes the teeth push each other. Without the chain on a gear, what transmits propulsion energy from motor to teeth? Would there be cogs that hopefully fell between the teeth to push them?   

bungston, Dec 09 2015

       Pushing rather than pulling on a system like this is baked, but I don't know of any cases where it's been successfully commercialized. (I saw it as a bike chain years ago).   

       If I were designing this, it would be linear motor powered, with each tooth on it's own carriage, but that's expensive. Alternatively, drive it with a friction wheel, or a toothed pulley that can still engage each tooth while the tooth is in contact with the next. None of those are difficult.   

       All of that being said, I don't think I'd get rid of the chain. A two axis flexing chain is a real thing, and it would work just fine for everything mentioned above except the splitting and recombining. You'd still have to design the anchor so the teeth could go around an inside corner, but that's doable.
MechE, Dec 09 2015

       I don't think I would have the skill to prototype not really patient enough. If the idea stimulates humanity to further advances, that's good enough for me.   

       The fit of each tooth might seal against swarf but I think escape channels would be necessary at choking points.   

       Could electromagnetic pulses be used to push multiple teeth and therefore mitigate the front tooth jam senario?   

       [Max] would that prototype actually work? You still want the cutting edge running in the direction of the track. A full U shaped tooth might make this work.
wjt, Dec 10 2015

       //would that prototype actually work? // Why not? You've still got a chainsaw, but with the cutting teeth set on one side of the chain, as opposed to on the outside edge of the chain. The teeth would need to be as wide as the chain-plus-support as viewed from the side, just as (in a conventional chainsaw) they need to be as wide as the chain-plus-support as viewed parallel to the plane of the blade.
MaxwellBuchanan, Dec 10 2015

       Due to forces and reactions involved, flex in the chain, structural integrity needed by the bar, the loss of bar cog, this prototype sounds flimsy. Making the teeth slightly bigger might help removing swarf down through the centre.   

       The trackblade was imagined to be more like a file where the teeth moved (extrapolating ultimately to a light sabre), though on failure, flying teeth would not be fun.
wjt, Dec 12 2015


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